Readers will have one more opportunity this week to pick the House and Senate races Roll Call will cover from the ground in the final weeks of the midterms.

Last week, thousands of votes were cast to send reporters @cahnemily and @alexis_levinson on the road in our first #RCReadersChoice survey. Two House races and two Senate races lead their packs, and now readers have until Thursday at 5 p.m. for the runoff contest.

On the Senate side, readers can select between Kansas, where GOP Sen. Pat Roberts is unexpectedly fighting for his re-election , and Colorado, where Democratic Sen. Mark Udall is attempting to fend off a strong challenge from GOP Rep. Cory Gardner. In the first round of voting , Kansas was the clear front-runner, and Colorado beat out the North Carolina Senate race by just two votes to make the final round.

The finalist House races are California's 52nd District, located in San Diego, and Nebraska's 2nd District, located in Omaha. Both incumbents in these races — Democrat Scott Peters in California and Republican Lee Terry in Nebraska — are on Roll Call's list of the 10 Most Vulnerable House Members .

Have an opinion on which race we should cover? Tweet your thoughts @RollCall with #RCReadersChoice. Otherwise, vote below:

Which Senate race — listed below in alphabetical order by state — should we send @alexis_levinson to cover from the ground?

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Which House race — listed below in alphabetical order by state — should we send @CahnEmily to cover from the ground next?